5.9l 1st gen 12v vs idi 6.9/7.3 pros and cons

[crashnzuk]

there is power available in the higher RPM range.... really there is.... trust me.... No they don't hold you in the seat as hard at the higher rpms but they still do - they start to fall on their face at 3k unless you change the cam grind....

That's kind of what I was getting at, the cam is designed for low revs. If you want to scream it, I would look into a cam swap. Call me crazy, but I don't mind my low revs. My 12cm housing works good too, even with the cold side being stock. EGT issues come in when you turn up the main fuel too much without corresponding air upgrades, so keep the fuel reasonable and you'll be ok.

And yes, I'm no fun. My tow rig is just that, not my toy. I want it to be as reliable and simple as an anvil.
Travis..

 

[safd1919]

well there isnt much todo as far of air intake other the like a k&n and a performance elbow..... a cam would be cool but at what cost??? and from where.... yes its a mix of a toy and dd

 

[82F100SWB]

The 3200 spring makes more of a difference than just where the engine defuels. It improves response throughout the RPM range, and with the 5 speed drivability is greatly improved, especially towing, the wide 2-3 gap is MUCH nicer to deal with when you can spin it up to around 28-2900 with it still pulling before you grab third.
The stock spring defuels around 2500 or so, and will allow about 2800. Mine with the curent pump settings starts to defuel around 3100 and will pull 3500 with the "3200 RPM" spring. And, yes, at 3500, it starts sounding like a 6 cyl Detroit at half the rpm...

 

[kas83]

The 3200 gov spring makes a huge difference in the fueling characteristics, as well as the governed rpm. The low to mid-range power difference is amazing.

Don't run an AirDog or other electric fuel pump, the mechanical pump will more than take care of a stock motors needs. Bump the fuel pressure up to 15-19 psi, throw an HX35 with a 14 cm gated housing so that you actually have some airflow, and some EDM's injectors with slightly raised pop pressure. Will make for excellent lowend grunt, great fuel mileage, and be very dependable.

As far as a rebuild, I've rebuilt a couple CTD's, and had about $1,200 in parts each time. I've priced rebuild kits for my IDI, and they are around $1,100 for everything. So it's comparable.

 

[garyjohnston]

I'd go with the cummins. Easiest things in the world to work on, and you can put it at 250 hp without buying any parts. If you wanted to completely make it performance in everything it would cost you less than 1500 for injectors, k&n, performance headers, fuel pin, 16mm turbo housing. All of the mods can be done yourself very simply. On the other hand I don't know much about IDI. The parts listed would put you about 400hp. Idk what the torque would be, it would vary. As for mileage, cummins is well known for it.